1. Field of the Invention
Exemplary embodiments of the present invention relate to a method for manufacturing a thin film transistor array panel.
2. Discussion of the Background
A thin film transistor may be used as a switching device to independently drive a pixel in a flat panel display such as a liquid crystal display or an organic light emitting diode display. A thin film transistor array panel includes thin film transistors connected to signal lines, e.g., gate lines and data lines that respectively transfer scan signals and data signals to the thin film transistor, and a pixel electrode.
As the display area of a thin film transistor array panel increases, the length of the signal line also increases. As a result, the signal line should include a low-resistance material. Copper has a low resistance and may overcome this problem.
However, when copper is exposed during a process for forming a contact hole on a passivation layer that protects the thin film transistor or during ashing of a photoresist pattern, the copper may react with material in the passivation layer, the photoresist pattern, or oxygen-containing compounds, thereby forming an impurity. The impurity may hinder etching in subsequent processes or may cause defects such as an electrical short if the copper in the signal line contacts other metal layers.
The above information disclosed in this section is for understanding of the background of the invention, and it may contain information that does not form the prior art.